/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    Remove.java
 *    Copyright (C) 1999 Len Trigg
 *
 */


package pATT.filters.unsupervised.attribute;

import java.util.Enumeration;
import java.util.Vector;

import pATT.core.Attribute;
import pATT.core.FastVector;
import pATT.core.Instance;
import pATT.core.Instances;
import pATT.core.Option;
import pATT.core.OptionHandler;
import pATT.core.Range;
import pATT.core.SparseInstance;
import pATT.core.Utils;
import pATT.filters.Filter;
import pATT.filters.StreamableFilter;
import pATT.filters.UnsupervisedFilter;

/** 
 * An instance filter that deletes a range of attributes from the dataset.<p>
 *
 * Valid filter-specific options are:<p>
 *
 * -R index1,index2-index4,...<br>
 * Specify list of columns to delete. First and last are valid indexes.
 * (default none)<p>
 *
 * -V<br>
 * Invert matching sense (i.e. only keep specified columns)<p>
 *
 * @author Len Trigg (trigg@cs.waikato.ac.nz)
 * @version $Revision: 1.4 $
 */
@SuppressWarnings("serial")
public class Remove extends Filter
implements UnsupervisedFilter, StreamableFilter, OptionHandler {
	
	/** Stores which columns to select as a funky range */
	protected Range m_SelectCols = new Range();
	
	/**
	 * Stores the indexes of the selected attributes in order, once the
	 * dataset is seen
	 */
	protected int [] m_SelectedAttributes;
	
	/** 
	 * Contains an index of string attributes in the input format
	 * that will survive the filtering process 
	 */
	protected int [] m_InputStringIndex;
	
	/**
	 * Constructor so that we can initialize the Range variable properly.
	 */
	public Remove() {
		
		m_SelectCols.setInvert(true);
	}
	
	/**
	 * Returns an enumeration describing the available options.
	 *
	 * @return an enumeration of all the available options.
	 */
	@SuppressWarnings("unchecked")
	public Enumeration listOptions() {
		
		Vector newVector = new Vector(2);
		
		newVector.addElement(new Option(
				"\tSpecify list of columns to delete. First and last are valid\n"
				+"\tindexes. (default none)",
				"R", 1, "-R <index1,index2-index4,...>"));
		newVector.addElement(new Option(
				"\tInvert matching sense (i.e. only keep specified columns)",
				"V", 0, "-V"));
//		"-R 1","-V"
		return newVector.elements();
	}
	
	/**
	 * Parses a given list of options controlling the behaviour of this object.
	 * Valid options are:<p>
	 *
	 * -R index1,index2-index4,...<br>
	 * Specify list of columns to delete. First and last are valid indexes.
	 * (default none)<p>
	 *
	 * -V<br>
	 * Invert matching sense (i.e. only keep specified columns)<p>
	 *
	 * @param options the list of options as an array of strings
	 * @exception Exception if an option is not supported
	 */
	public void setOptions(String[] options) throws Exception {
		
		String deleteList = Utils.getOption('R', options);
		if (deleteList.length() != 0) {
			setAttributeIndices(deleteList);
		}
		setInvertSelection(Utils.getFlag('V', options));
		
		if (getInputFormat() != null) {
			setInputFormat(getInputFormat());
		}
	}
	
	/**
	 * Gets the current settings of the filter.
	 *
	 * @return an array of strings suitable for passing to setOptions
	 */
	public String [] getOptions() {
		
		String [] options = new String [3];
		int current = 0;
		
		if (getInvertSelection()) {
			options[current++] = "-V";
		}
		if (!getAttributeIndices().equals("")) {
			options[current++] = "-R"; options[current++] = getAttributeIndices();
		}
		
		while (current < options.length) {
			options[current++] = "";
		}
		return options;
	}
	
	/**
	 * Sets the format of the input instances.
	 *
	 * @param instanceInfo an Instances object containing the input instance
	 * structure (any instances contained in the object are ignored - only the
	 * structure is required).
	 * @return true if the outputFormat may be collected immediately
	 * @exception Exception if the format couldn't be set successfully
	 */
	public boolean setInputFormat(Instances instanceInfo) throws Exception {
		
		super.setInputFormat(instanceInfo);
		
		m_SelectCols.setUpper(instanceInfo.numAttributes() - 1);
		
		// Create the output buffer
		FastVector attributes = new FastVector();
		int outputClass = -1;
		m_SelectedAttributes = m_SelectCols.getSelection();
		int inStrKeepLen = 0;
		int [] inStrKeep = new int[m_SelectedAttributes.length];
		for (int i = 0; i < m_SelectedAttributes.length; i++) {
			int current = m_SelectedAttributes[i];
			if (instanceInfo.classIndex() == current) {
				outputClass = attributes.size();
			}
			Attribute keep = (Attribute)instanceInfo.attribute(current).copy();
			if (keep.type() == Attribute.STRING) {
				inStrKeep[inStrKeepLen++] = current;
			}
			attributes.addElement(keep);
		}
		m_InputStringIndex = new int [inStrKeepLen];
		System.arraycopy(inStrKeep, 0, m_InputStringIndex, 0, inStrKeepLen);
		Instances outputFormat = new Instances(instanceInfo.relationName(),
				attributes, 0); 
		outputFormat.setClassIndex(outputClass);
		setOutputFormat(outputFormat);
		return true;
	}
	
	
	/**
	 * Input an instance for filtering. Ordinarily the instance is processed
	 * and made available for output immediately. Some filters require all
	 * instances be read before producing output.
	 *
	 * @param instance the input instance
	 * @return true if the filtered instance may now be
	 * collected with output().
	 * @exception IllegalStateException if no input structure has been defined.
	 */
	public boolean input(Instance instance) {
		
		if (getInputFormat() == null) {
			throw new IllegalStateException("No input instance format defined");
		}
		if (m_NewBatch) {
			resetQueue();
			m_NewBatch = false;
		}
		
		if (getOutputFormat().numAttributes() == 0) {
			return false;
		}
		double [] vals = new double[getOutputFormat().numAttributes()];
		for (int i = 0; i < m_SelectedAttributes.length; i++) {
			int current = m_SelectedAttributes[i];
			vals[i] = instance.value(current);
		}
		Instance inst = null;
		if (instance instanceof SparseInstance) {
			inst = new SparseInstance(instance.weight(), vals);
		} else {
			inst = new Instance(instance.weight(), vals);
		}
		copyStringValues(inst, false, instance.dataset(), m_InputStringIndex,
				getOutputFormat(), getOutputStringIndex());
		inst.setDataset(getOutputFormat());
		push(inst);
		return true;
	}
	
	/**
	 * Returns a string describing this filter
	 *
	 * @return a description of the filter suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String globalInfo() {
		
		return "An instance filter that removes a range of attributes from the \n"
		+"dataset.";
	}
	
	/**
	 * Returns the tip text for this property
	 *
	 * @return tip text for this property suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String invertSelectionTipText() {
		
		return "Determines whether action is to select or delete."
		+ " If set to true, only the specified attributes will be kept;"
		+ " If set to false, specified attributes will be deleted.";
	}
	
	/**
	 * Get whether the supplied columns are to be removed or kept
	 *
	 * @return true if the supplied columns will be kept
	 */
	public boolean getInvertSelection() {
		
		return !m_SelectCols.getInvert();
	}
	
	/**
	 * Set whether selected columns should be removed or kept. If true the 
	 * selected columns are kept and unselected columns are deleted. If false
	 * selected columns are deleted and unselected columns are kept.
	 *
	 * @param invert the new invert setting
	 */
	public void setInvertSelection(boolean invert) {
		
		m_SelectCols.setInvert(!invert);
	}
	
	/**
	 * Returns the tip text for this property
	 *
	 * @return tip text for this property suitable for
	 * displaying in the explorer/experimenter gui
	 */
	public String attributeIndicesTipText() {
		
		return "Specify range of attributes to act on."
		+ " This is a comma separated list of attribute indices, with"
		+ " \"first\" and \"last\" valid values. Specify an inclusive"
		+ " range with \"-\". E.g: \"first-3,5,6-10,last\".";
	}
	
	/**
	 * Get the current range selection.
	 *
	 * @return a string containing a comma separated list of ranges
	 */
	public String getAttributeIndices() {
		
		return m_SelectCols.getRanges();
	}
	
	/**
	 * Set which attributes are to be deleted (or kept if invert is true)
	 *
	 * @param rangeList a string representing the list of attributes.  Since
	 * the string will typically come from a user, attributes are indexed from
	 * 1. <br>
	 * eg: first-3,5,6-last
	 */
	public void setAttributeIndices(String rangeList) {
		
		m_SelectCols.setRanges(rangeList);
	}
	
	/**
	 * Set which attributes are to be deleted (or kept if invert is true)
	 *
	 * @param attributes an array containing indexes of attributes to select.
	 * Since the array will typically come from a program, attributes are indexed
	 * from 0.
	 */
	public void setAttributeIndicesArray(int [] attributes) {
		
		setAttributeIndices(Range.indicesToRangeList(attributes));
	}
		
	@Override
	public boolean isSupervisedFilter() {
		return false;
	}
	
	@Override
	public boolean isAttributeFilter() {
		return true;
	}
	
	@Override
	public String moreInfo() {
		return globalInfo();
	}
	
	@Override
	public boolean hasDataInput() {
		return true;
	}
	
	@Override
	public String more() {
		return super.more(listOptions());
	}
	
	@Override
	public String getOption(String label) {
		if(label.equals("V"))
			return "invertSelection";
		else if(label.equals("R"))
			return "attributeIndices";
		
		return "";
	}

	@Override
	public void cleanFields() {
		m_SelectCols = new Range();		
	}
}


